土壤镉暴露对玉米和大豆的生态毒性评估

以中国东北黑土为培养基,通过室内急性毒性实验,采用Trimmed Spearman-Karber方法计算EC50值(半抑制浓度),并分析作物的生物累积系数(BAF),定量化评估了土壤中镉对玉米和大豆的生态毒性及生物有效性.测量终点为种子发芽率、根长和幼茎长.结果表明,土壤镉暴露给农作物带来一定的负生长效应.种子发芽率不是评估土壤镉生态毒性的敏感因子,根生长是敏感的毒性测量终点.镉在植株体内的累积及迁移与作物种类和土壤镉浓度有关.玉米植株体内累积了较大量的镉,而大豆植株体内镉由根向幼茎的迁移较为显著.

Ecotoxicity assessment of cadmium in soil to maize (Zea mays) and soybean (Glycine max)

Ecotoxicity and bioavailability of cadmium (Cd) to maize (Zea mays) and soybean (Glycine max) were investigated by acute toxicity tests in laboratory with black soil as medium. Ecotoxicity and bioavailability of Cd were quantified by calculating the median effective concentration (EC_ 50 ) and bioaccumulation factor (BAF). The measurement endpoints used were seed germination and seedling growth (shoot and root). The results showed that Cd concentrations in soil had adverse influence on the growth of roots and shoots. Seed germination was not the suitable indicator for the ecotoxicity of Cd in soil, while the growth of roots was the most sensitive measurement endpoint. Bioaccumulation and transport of Cd within plants depended on the test crop species and Cd concentrations in soil. The maize retained more Cd in its roots, while the soybean transported more Cd to the shoots from roots.